INDIVIDUALITY. 85 



process ; and of the others, from their close affinity, we cannot 

 doubt that they reproduce themselves in the same way. This 

 is, in one sense, then, a negation of the old aphorism: "Omne 

 vivum ex ovo" "All life comes from an egg" 



I have not, by any means, begun to exhaust the numerous 

 instances in which individuals originate without passing through 

 the condition of an egg. The process of budding prevails not 

 only among the lowest forms, as I have shown, but it occurs 

 among animals which are higher in grade than the Worms; it 

 occurs among certain shrimp-like animals, called " water-fleas," 

 which are related to crabs and lobsters ; and it occurs among In- 

 sects. It is common among certain forms of Shell-fish, Bryozoa, 

 (see chap, xi.) Finally, we have it even in Vertebrates, especially 

 among Fishes ; as Lereboullet has recently shown to prevail to 

 a great extent. Sometimes, according to this observer, an egg 

 divided into two fishes ; sometimes the division was only partially 

 carried out, and the result was a 

 fish with two heads, (fig. 45,) or 

 two tails, or two heads and two 

 tails and the body single. It is 

 very seldom that full-grown fishes 

 are found in this condition, because 

 they are more or less helpless and 

 unable to defend themselves or 

 escape from an enemy. It is not a 

 very rare thing to find full-grown 

 snakes with two heads or two tails. Dogs, cats, calves, &c., have 

 been born, and have grown up, with an increased number of 

 heads or legs ; and even Man seems not always to have been 

 contented with one head. Isidore St. Hilaire has recently pub- 

 lished a work in which he has given a great number of examples 



Fig. 45. Esox Indus. L. A double-headed embryo of the Pike of Europe, 

 magnified 20 diam. h, A 1 , the two heads ; 6, 6 1 , the anterior half of the body of 

 each; b~, the junction of 6, ', which continues single to the tail (<) The whole 

 lies on the surface of the yolk, and is as yet enclosed within the egg-shell. 

 From Lereboullet. 



